Pacific Loon

Pacific Loon (Gavia pacifica) is a sleek diving bird whose breeding plumage combines a grey head, black throat and fine vertical black-and-white stripes on the neck. Body shape, bill structure, plumage pattern and voice provide the strongest field characters. Age, sex and season may alter its appearance, so identification should combine several features and careful direct field comparisons with similar species in the same habitat (Wikipedia, general species account).

It breeds on tundra lakes, migrates to Pacific coastal waters and catches fish and other aquatic prey during long underwater pursuits powered by its feet. Its movements and social behaviour vary through the year, with breeding birds generally more dispersed and non-breeding birds gathering where food is concentrated. Japanese records place it within the country's documented avifauna as a resident, migrant or visitor (Wikipedia, general species account; Wildlife of Japan occurrence records).